查看 draw.io 。它可以免费使用，并且可以让您了解基础JavaScript库的功能。

How to draw sequence diagram in javascript/HTML? I've seen some charting library like JS chart, Emprise javascript chart etc... but those do not support sequence diagram. Also seen JointJS (http://www.jointjs.com/), but this library also don't support sequence diagram.

Have a look at draw.io. It's free to use and it gives you an idea what the underlying javascript library is capable of.